Various types of shaft couplers have been known for many years. In particular, small gasoline engines are typically provided with a shaft having a keyway therein for receipt of a key which in turn interlocks with a coupler having a corresponding bore and keyway therein. Typically, the coupler has a set screw which bears against the key to lock the coupler to the shaft. Such devices tend to loosen and shear the key or otherwise hurt the integrity of the coupling when subjected to high loads, particularly when such loads are varying in nature.
It is therefore an object of this invention to provide a coupler for keyed shafts which is effective in high loads which vary in magnitude and which may be easily and inexpensively manufactured.